1. Field of the Invention
The invention relates to an apparatus for measuring the total surface area of catalytic metal particles.
2. Description of the Relates Art
A catalyst for purifying injurious gases in the exhaust gas discharged from an engine is known. The catalyst comprises a carrier having pores therein and catalytic metal particles carried on surfaces of the pores of the carrier. The character of the catalyst depends on total surface area of the catalytic metal particles per unit weight, i.e., a specific area and a distribution of the radii of the pores. For example, in Japanese Unexamined Patent Publication (Kokai) No. 2-55213, a specific surface area of a catalyst is measured by a BET type specific surface area measure, and the distribution of the radii of the pores is calculated or the basis of an adsorption isotherm and a relative pressure.
The character of the catalyst also depends on a distribution of the surface areas of the catalytic metal particles relative to the radii of the pores. However, the distribution can not be measured by the technique disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2-55213.